Metal concrete for hearth plates and the like



Patented Get. 27, 1931 UNITED STATES PATENT OFFICE HENRY a. HARRIS, or nmnbrr, MICHIGAN METAL CONCRETE FOB HEARTH PLATES AND THE LIKE No Drawing. Boiled for abandoned application Serial No. 725,089, filed July 9, 1924. This application filed Kay 9, 1888.

My invention relates to metal concrete adapted for use in furnace hearths and the like, which, in order to stand up in use over long periods, require a substantially infrangible material, that is resistant to wear and resistant to high temperatures, as for example, temperatures of 1000 to 2300 F.

Metals such as alloys of nickel, chromium and iron have good strength and resistance to scaling at high temperatures, but are expensive and lacking in wear resistance, particularly in case the surface area is small or subdivided.

Materials such as carbide of silicon, commonly known as carborundum, have good wear and heat resisting qualities, but are relatively frangible, and hearths made up of bricks or plates thereof will fail due to cracking and breakage taking place when sub 0 jected to high temperatures and to shocks in use.

By providing a metal concrete containin pieces or granules or carborundum imbedde in cast alloy of the kind above referred to,

all the advantages of both without the disadvantages of either, and s0 secure a material which is relatively infrangible, the nickelchromium-iron alloy binding the hard pieces of carborundum so evenly and thoroughly together that destructive cracking does not occur, and which material is resistant to Wear and resistant to scaling away at high temper atures.

While I have described my preferred filler as being composed of silicon carbide, commonly known as carborundum, oxides of metals such as aluminum, compounds of silicon and aluminum, and the like may else be employed.

For the matrix orbinder for metal concrete to be subjected to the higher temperatures such as around 2300 F. Ipreferably make use of an alloy composed of about 68 parts nickel, about parts chromium, and the balance largely iron. Metal concrete consisting of a filler of carborundum and a bind- I er of such nickel-chrome alloy not only withstands temperatures up to 2300 F., but rev 50 sists abrasion for long periods of time.

or equivalent thereof, I am enabled to obtain Serial R0. 276,512.

Other binder materials can be employed ac- I larger percentage of iron with the addition of nickel and chromium may be employed where the temperatures are as low, as 1000 F. to 1200 F. And I may also vary the proportion of binder to filler so as to provide an open or closed structure and otherwise control the physical properties of the metal concrete casting.

In manufacturing my new metal concrete I prefer to employ carborundum cr stals or granules of a size depending upon t e use to which the article is to be put, for hearth plates for heat treating furnaces, for instance, I may employ granules. The granular substance and the binder may be mixed in a ladle, poured into a mold, or the mold may be filled with the granules and the-binder poured in, filling the voids between the granules, or the molten binder and the granules may be poured together, according to any of the several processes well known in the art. Thus granular particles may be either loosely or tightly pac ed in a suitable receptacle and a lid having an openin therein placed thereon whereupon the bin er may be poured into the receptacles filling the crevices between the particles. In case the particles do not completely fill the receptacle or are loosely packed therein a resultant material will be had in which the filler will constitute one face while the granular particles will be quite in evidence at the other face, the center showing a corresponding graduation in constituency from one to the other while if the particles are packed quite tightly the particles will remain wedged in the respective positions when the binder is poured in the receptacle thereby distributing the particles as evenly throughout the resultant product as they were placed in the beginning. In each of these cases, the final form of the article is determined by casting. be understood that in casting, the crystalline or granular material may be heated or not, according to the final result desired to be obtained; also that the tightness or looseness of the bond can be varied by changing the It will also I pourin temperature and the temperature of the granular substance, and modifications may be resorted to within the scope of the appended claims.

I claim:

1. As a new article of manufacture, a metal concrete adapted for use in furnace hearths, linings, and the like, which is substantially infrangible, highly Wear resisting and resistant to high temperatures, and comprises pieces of relatively frangible filler highly resistant to wear and to high temperatures, and a cast binder of an alloy consisting principally of nickeland chromium having such filler imbedded therein, said binder being resistant to high temperatures, and relatively strong and infrangible at such temperatures.

2. As a new article of manufacture, a metal concrete adapted for use in furnace hearths, linings, and the like, which is substantially infrangible, highly wear resisting and resistant to high temperatures, and comprises pieces of relatively frangible filler highly resistant to wear and to high temperatures, and a cast binder of an alloy consisting substantially entirely-of nickel, chromium and iron having such filler imbedded therein, said .binder being resistant to high temperatures,

and relatively strong and infrangible at such temperatures.

3. As a new article'of manufacture, a metal concrete adapted for use in furnace hearths, linings, and the like, which is substantially infrangible, highly wear resisting and resistant to high temperatures, and comprises pieces of relatively frangible filler of silicon carbide highly resistant to wear and to high temperatures, and a cast binder of an alloy :onslsting principally of nickel and chromium having such filler imbedded therein, said binder being resistant to high temperatures, and relatively strong and infrangible at such temperatures.

4. As a new article of manufacture, a metal concrete adapted for use in furnace ing such filler, and which is composed of a. ferrous alloy containing chromium and nickel aggregating approximately half or more of the total content, and is highly resistant to oxidation and substantially devoid of free scale at high temperatures of heat treating furnaces, both filler and binder being exposed at and forming a surface highly stable and highly resistant to wear at such heat.'

In testimony whereof Iafiix my signature.

HENRY H. HARRIS.

hearths, linings, and the like, which is substantially infrangible, highly wear resisting and resistant to high temperatures, and comprises pieces of relatively frangible filler of silicon carbide highly resistant to wear and to high temperatures, and a cast binder of an alloy consisting substantially entirely of nickel, chromium and iron having such filler imbeddedtherein, said binder being resistant to high temperatures, and relatively strong and infrangible at such temperatures.

5, A new composition of material that is substantially infrangible and non-warping and wear-resistant at high temperatures comprising pieces of non-metallic heat and wearresisting refractory material of the nature of silicon carbide, which in mass formation is frangible, constituting a filler, and a cast matrix of metallic binding material, contain- 

